#include "apue.h"
#include <sys/wait.h>

#define PAGER   "${PAGER:-more}"

int main(int argc, char *argv[])
{
    char    line[MAXLINE];
    FILE    *fpin, *fpout;

    if (argc != 2)
        err_quit("usage: a.out <pathname>");

    if ((fpin = popen(argv[1], "r")) == NULL)
        err_sys("can't open %s", argv[1]);

    if ((fpout = popen(PAGER, "w")) == NULL)
        err_sys("popen error");

    while (fgets(line, MAXLINE, fpin) != NULL)
    {
        if (fputs(line, fpout) == EOF)
        {
            err_sys("fputs error to pipe");
        }
    }

    if (ferror(fpin))
        err_sys("fgets error");
    if (fclose(fpout) == -1)
        err_sys("pclose error");

    exit(0);
}
